


A little secret that you shouldn't know

by Cinicalamente



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Accidental Voyeurism, Bathing/Washing, Flash Fic, Late Night Conversations, M/M, Pre-Relationship
Language: English
Status: Completed
Published: 2020-01-27
Updated: 2020-01-27
Packaged: 2021-02-27 10:29:13
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,561
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22365664
Author URL: https://archiveofourown.org/users/Cinicalamente/pseuds/Cinicalamente
Summary: Summertime nights are misterious, now Senkuu knows it for sure. He can't talk about it neither because he shouldn't be there but he can't help.
Relationships: Asagiri Gen & Ishigami Senkuu, Asagiri Gen/Ishigami Senkuu
Comments: 14
Kudos: 128





	A little secret that you shouldn't know

**Author's Note:**

> New little sengen fanfiction! I miss them so much so I write this even I should be studying rip. Don't forget to comment and show me what you think about this story or my ffs in general because I'm thirsty for comments 🤧🙏  
> Anyway, english is not my native language so sorry for mistakes! :3

The moon was high in the sky and although it was full, its light was only obscured by the multitude of stars that dominated the sky. Senkuu sighed and, since he had been up to then with his nose up, he lowered his head and rubbed the back of his neck with his hand. The summer nights were warm, but the beauty of the sky compensated the pain for those extra degrees... not to mention that Senkuu could admire his beloved stars even without the telescope.

  
  


To prevent Chrome from waking up, when the heat didn't make him sleep, Senkuu walked to the edge of the woods, looking more at the sky above him than where his feet rested.

Luckily he was not so clumsy to stumble, but more than once he had risked falling under the eyes of some perching owl around there.

Occasionally, however, he also walked in the residential area of the village to check that he was the only one awake.

That evening, he noticed Gen's empty bed again. The Mentalist shared the hut together with other boys from the Village and Senkuu immediately wondered if his absence was caused by relationship problems, although he knew very well that Gen had the right word at the right time.

Now that he thought about it, it was when the summer nights got hotter that Gen spent the night who knows where. There was no longer the possibility that he had reunited with the Tsukasa's side, considering that the two empires had now joined. There was also the possibility that he slept in the other settlement a couple of kilometers from the village since in the morning he always crossed the bridge to reach the laboratory.

Senkuu also ruled out the option to ask Gen directly. He should have given too many explanations about it and, since he had never met him while walking at night, he meant that he probably hadn't strayed so far from the Village or through the woods, potentially a source of danger for a lazy person like him.

Without realizing it, however, Senkuu was entering the forest, moving along the path that led to the river where the villagers collected the water, at the foot of the waterfall from which he had repeatedly risked falling. He grimaced as he remembered the last time that only thanks to Kohaku had he not fallen and been dragged by the current.

Considering he was sweaty, he thought it wouldn't be a bad idea to cool off at the river.

Under the rays of the moon, he managed to reach the shore and almost overcome the trees, the natural screen of the canal. However, he noticed something unusual and stopped just in time.

Some folded clothes lay on the grass. There was also a towel, which Senkuu recognized as the one he had personally worked on during last spring. It had to be someone from the Village... well, not that there were so many options at the end.

The cave had been destroyed, Tsukasa was in a freezer, and he was the only one who knew how to produce the miraculous fluid.

There was also the possibility that someone, very loyal to the strongest primate in the world, had intended to awaken someone, but it was impossible that they had arrived at the village without anyone noticing.

Senkuu narrowed his eyes to take a closer look at the pile of cloth on the ground and was quite sure he could catch colors that seemed dark in the dim moonlight. He looked around. After all, the owner of those clothes must have been nearby. It was then that he stared at the water, expecting from one moment to another to come out a person (or more than one? Who could have known?) and finally reveal the arcane.

Senkuu stood still and, when he noticed Gen's two-tone hair wrinkling the surface, he insulted himself mentally for not having connected things. It was possible that someone else was there, but since Gen too used to wake up at night, because of the too hot weather, he could understand that it was the Mentalist who was swimming in the river.

The boy then, unaware of being observed and of Senkuu's strange hypotheses, moved his wet hair from his face and continued to move in the water without giving any sign of wanting to go out. He seemed incredibly comfortable there and nearly Senkuu didn't want to join him. There was nothing wrong after all... he would have called him as soon as he got out of his hiding place (it was foolish that he was still hidden anyway… there were no dangers in sight) so as not to frighten him and he would take off his shoes to cool off a bit.

It was just Gen, he had no reason to feel so strange.

Contrary to his intentions, Senkuu clung to the trunk of the tree and brought his gaze to the silhouette of the Mentalist who darted in the water.

He smiled slightly and crossed his arms as he changed his position not to be seen and at the same time to look at him better. He turned to the other side of the tree and leaned back against the bark.

When Gen rose to his feet - he could very well stay upright and touch the river bed - drops of water rushed down his chest. Senkuu could barely follow their journey, he did not have Kohaku's super eyes and the light of the moon and stars was not so powerful... however he concentrated on the contracted muscles of his arms while Gen lifted them to squeeze the tips of his wet hair or those of the legs while bending down to play with some pebbles on the bottom of the river.

Senkuu did not remember ever seeing Gen without clothes.

In fact, the Mentalist was modest, had never changed in front of anyone and did not remove any of the numerous layers of fabric that covered him even in the hot ones. Maybe he wasn't comfortable with his body... maybe because of past accidents. He had read that the entertainment world knew how to be cruel to perfection standards. Senkuu thought it was nonsense. They were in Stone World, the priorities of life and survival were different from those of the pre-petrification civilization.

In fact, by sharpening his eyes, he could see when Gen's body was in shape and did not disfigure without clothes. Senkuu swallowed in caressing him with his eyes. His mouth had suddenly dried up.

_ 'With nights so hot it was rather obvious that it would happen,' _ Senkuu thought. 'That bastard of Asagiri Gen was taking too long,' he continued. After all he could get moving and give him the chance to cool off.

In response, Gen went swimming again, waving his legs and arms.

Senkuu shook his head and thought of the folded robes. He was swimming naked unless he removed his slip first, hiding it in the folds of his kimono.

He hadn't recognized Yuzuriha's hand behind the seams of his clothes, so the question was what the resources for clothing were as soon as Gen was awakened. Most likely he wasn't wearing underwear at all and... Senkuu felt the tips of his ears warm. The whole face was actually blushing.

Even Senkuu himself did not have underwear, but there was no reason to blush at the thought that Gen was without any dress in the water. It had been the most logical choice, especially considering it was only while swimming in the river.

Maybe, maybe it was better if he left. He would wet his wrists in some water in the small cistern he had built and go back to sleep. Gen thought he was alone and didn't need to find out that he wasn't.

Paying attention to where he stood, Senkuu returned to the Village, fighting against the images that his mind had begun to replicate.

***

The following night the same scene was repeated.

It was hot, Senkuu did nothing but roll on the blanket - the least hot of those in their inventory - that he and Chrome had spread in the middle of the room without being able to sleep. He stayed for a while listening to the snoring of Chrome who slept blissfully, but he couldn't fight with the need to get up and take his usual walk. Maybe he could have cooled off in the water of the river where he had found the mentalist the previous night.

Perhaps he would see Gen again as he swam and let himself be embraced by the fresh water. Not that he cared to see him swim without clothes, of course, it was to remember not to go away and actually wait for his turn this time.

Senkuu grunted at the inconsistency of his thoughts, but got up anyway. He put on his shoes and storage belt before leaving the room without looking back.

***

Having overcome the amazement of the first night, Senkuu now expected to see Gen there. As soon as he arrived near the river, he had paid more attention and had hidden in the same place as when he had been there the first time. Even the mentalist's robes were folded in the same order as yesterday, even his head peeked out from the water level like the last time he saw him.

Considering that Gen hadn't mentioned the river and hadn't accused him of spying on him, Senkuu hoped he wasn't discovered. He almost looked like a thief as he moved silently and was heartbreaking at the mere thought that he could be accused of a fault he had actually committed and was inexplicable.

It was relaxing to watch Gen swim in the moonlight without clothes.

Senkuu bit his lip without turning his head as soon as Gen got back on his feet. He leaned against the trunk, being careful not to enter the other's visual picture and stood looking at him, fascinated by the drops of water that drew lines intended to absorb himself on his body. Gen had a minute physique that, due to his height, seemed more fragile. Senkuu could see how well the body of Gen was well proportioned and slim. He continued to torture his lower lip with his teeth while with his gaze fixed on Mentalist' shoulders turned against the bark of the tree in search of a more comfortable position. He raised his arm to support his head as if he could stretch from one moment to another vertically. He propped his left hand at the waist, slipping his fingers between the fabric straps that held the bags firmly to the belt of his robe.

Gen turned (in Senkuu it seemed to him, which made his heart jump in his throat) and, gathering some water with the palms of his hands, he threw it into the air to make the splashes rain on his naked body. The mentalist smiled and Senkuu leaned forward, holding on to the trunk, to look at him better.

In the light of the moon reflected by the water, Asagiri Gen shone. It was a breathtaking vision, Senkuu agreed to himself, and almost slipped to the shore, revealing his position.

_ 'Looking at something fascinating was intrinsic in human nature!' _ Senkuu thought as he stood on his toes to follow the movements of the man in front of him. It was natural to want to look at something beautiful, after all he was still a scientist interested in explainable dynamics and which acted as a fuse to a chain of reactions and...

Senkuu licked his lips, breathing through his mouth to not risk suffocation. There was something strange in his breathing and yet he found himself looking at men without clothes several times (in the Stone World there was and there is need for practicality after all!) And it never had this effect. Senkuu was curious by nature, curiosity moved the search for answers... it was a blessing, but in this case it could be a dangerous double-edged sword. In a push given by the decision, the young scientist turned around, turning his back on Gen, and marched into the forest to return to the Village.

After a few meters, Senkuu stopped and covered his face with his hands.

"Ahhh, mentalist," he chanted against the skin of his palms. He noticed that his cheeks were on fire. "You will drive me crazy in one way or another... Gen..."

***

After dinner and until Chrome had lain exhausted from the day's fatigue beside him, Senkuu had forced himself not to get up, but as soon as Chrome started to snore, his good intentions were all about to fade. It was recommended by all doctors to walk before bed and especially in the summer heat that was gripping Japan, it was important to stay hydrated! His mind tried in every way to justify his transgression. However Senkuu turned and, lying on his stomach, looked up at the entrance of the room. The sky was as splendid as every night. He wondered if Gen was already in the river and if the water was already lapping on his fair skin: his back, his hair still swollen on his neck, his arms, his hips, his butt, his...

"Fuck!" He mumbled, lowering his head against the floor with too much force to hurt himself. He squeezed his eyes and teeth from the impact. "Enough now, I have to go out," he said to himself, sitting up to tie his shoes. "I have to… go," he murmured without realizing that he had used the voice that faded between the noises that his belt made while banging on the floor.

"Sen... Kuu?" Chrome whispered, narrowing his eyes and making Senkuu stiffen. "What..."

"I have to urinate," he lied, "or do you prefer me to do it here?"

"Bleah," said the young man and turned to the other side.

Senkuu got up and after snickering at the kneading voice of the person who fell asleep as soon as he touched the pillow, he went out and continued with his original plan.

The good intentions never remained only intentions... Or good at all.

***

Two weeks had passed. Senkuu was used to counting (he had been doing it for more than 3700 years, after all), but counting those 14 nights proved more difficult than expected.

Each night continued to be the same as the previous one.

Senkuu tried not to give in, but eventually he walked to the river and his hiding place to watch Gen, who continued to be in the water playing and swimming. The Mentalist's clothes were always folded to the shore and the branches that Senkuu dodged so as not to make noise were still in the same place among the blades of grass.

However it was Senkuu - even if he didn't want to admit it to himself - that changed. His attitude was different. It had all happened in a hurry and the dose of emotions he had felt in these nights had pushed Senkuu to ask himself what his life could bring and above all he wondered even if it was right to try them in secret, to the detriment of Gen's privacy.

_ 'It was wrong,' _ he repeated it even as he walked to the river and lurked behind the usual tree, waiting to find the exact position of Gen in the water. Then he simply looked at him, taking note of all the changes in his body, how that was not the right way to ogle a friend without clothes on. It was ethically wrong, but his breathing became more frenetic, the thin fabric of his robe was glued to his sweaty skin and when Gen got up, escaping from the water level, Senkuu leaned over and grumbled asking to show him more. His voice was hardly audible, but the fact that Gen could have heard him from one moment to another made everything more erotic than it was already.

"Fuck," Senkuu gasped, taking advantage of the moment when the Mentalist swam to close his eyes and relax against the tree. His body night after night had become fiery, he almost seemed to have forgotten his instructions for working properly.

And came the seventeenth evening, when Senkuu had found himself falling asleep despite the heat from too much fatigue. The next morning, the young Ishigami was furious and barricaded himself in the laboratory, denying anyone, even Ryuusui, who wanted to talk to him about his new money: the Dragos.

Senkuu could not believe that he had missed that important moment! It was practically the favorite moment of the day! His night walk! Not Gen naked in the river, of course... even if he tried to tell himself and to seem credible with himself, it was impossible.

Senkuu wanted to see Gen play with water and the rays illuminate him in the river. He wanted to feel his body awaken to the excitement of looking at the Mentalist without clothes, murmuring his name in a low voice as he watched him caress himself to shake off the drops of water that had the privilege of touching him.

Senkuu was now aware that he wanted to contemplate him even more, more and maybe reach him, run his fingers along his back, bring his lips close to the lobe of his ear to ask him if he liked his touch and then who knows what more...

He leaned against the table, feeling a trickle of drool run down his chin... it was embarrassing to admit it, but his instincts were there to torment him and he wanted to be tormented, but alone he was not the same.

"Fuck, tonight..." he snapped, grabbing the edges of the lab table. "Tonight," he repeated that expectant word, unable to decide even what he should do to get closer to the person of his desires.

But he was Ishigami Senkuu and the word surrender was not part of the lemma of his dictionary.

***

That night, Senkuu didn't even pretend to be asleep. He let Chrome climb into the room and he stayed in the lab as he finished deciding what to do with Ryuusui's pressing request for oil. As soon as the noise in the village subsided, sign that they were all in bed by now, he got up and, stretching, closed all the parchments he had been working on until then. He left the laboratory to go to the river, trying to find some possible phrase to justify both his presence there and his haste.

He slowed down as soon as he recognized the large tree behind which he sheltered and moved one of the low branches to look at the shore, but it was not easy to hold back a line of disappointment.

Gen's clothes, usually folded and placed next to the sheet, were not there. Maybe he was early... maybe the desire to see him again had betrayed him and pushed him to change the time of his usual walk. He took a few steps towards the river to accept that he was alone.

He looked around, but the Mentalist was not there.

Senkuu sat on the lawn and watched the water flow, regardless of his thoughts about Gen's absence. It was early, it was the only reason he accepted at the moment. Gen could not fail to go to the river and above all he could not have missed it. Senkuu crossed his legs, feeling the air penetrate the fibers of his robe, splitting the skin not protected by the underwear. He spread his legs, suddenly feeling awkward about that, but couldn't deny that it was a pleasant feeling. He closed his eyes and put both hands on the grass to support himself.

If he could have watched Gen while playing with the water, he would have appreciated that moment more. Mainly because he would have been in the front row, comfortably seated and could have looked him in the eyes as he wiped every inch of his body before getting dressed (a moment he had only seen twice because he had dared a little more than the usual escape to not be found there). He stretched out and folded his arms to support his head.

Everything would have been better with Gen.

***

Senkuu felt something press against his left leg. He did not remember falling asleep or returning to the village and the sound of the water confirmed that he was still to the river. His eyes widened on alert, but as soon as he distinguished the figure of Gen at his side, he was only surprised to have been discovered.

"Good morning, Senkuu-chan!" he greeted him in a low voice. "Actually it's still night so I shouldn't say good morning..."

"When did you arrive?" Senkuu asked him, sitting for looking at him. His shoulder touched that of Gen, who was also sitting on the grass.

"For a while... I watched you sleep because you had such a sexy grin on your face... who knows what you were doing to me in your dream," Gen replied, arching an eyebrow. His voice stirred something in Senkuu, who lay back on the lawn as he was silent.

"Ah, do you think I was dreaming you?" He replied, biting his lip, "why are you so sure, Mentalist?"

Gen put his hand to hair to move the longer lock behind his ear and leaned over Senkuu. His eyes were darker and Senkuu doubted it was because of the little light in that position.

"Dreams are the reworking of thoughts in the form of stories and memories when our body rests," Gen explained and Senkuu stared at his body wondering when Gen wanted to sit on his lap, but the Mentalist did not fulfill his wish. "And I'm pretty sure you had a lot of interesting thoughts considering you were always here looking at me... when I'm without clothes on..."

Gen could read behind his actions even before he found an explanation by himself. Senkuu smiled and narrowed his eyes, determined to listen to more before confirming what Gen was saying. Apparently he had found out but hadn't stopped him. Gen however did not continue.

The mentalist stood there looking at him.

"Senkuu-chan..." he called after a few minutes.

Senkuu covered up the strange feeling that gripped his stomach. "Uhm?"

"Do you want to help me undress me? Or did you get tired of seeing me naked?"

_ Fuck. _

Senkuu didn't see that coming. He just breathed deeply. He had a choice to make.

"You're overestimating yourself, Mentalist," he pretended disinterestedly as he felt the warmth of Gen's body so close to his. "This kind of thing doesn't matter to me for the moment. If I distracted myself or put my pleasure before having to rebuild civilization, I would fail in my own mission."

Gen was not intimidated by his statement. He simply got up and took off the first layer of cloth that covered him. "Oh Senkuu-chan, then I won't disturb you further. Go ahead, sleeping in the woods isn't very safe..."

"And you..."

"I'm a little late for my night bath, but it's very hot, isn't it?"

"Yes, it's incredibly hot," Senkuu agreed, staring at Gen's fingers as they untied the laces on his collar. "Very hot."

The mentalist turned, taking away the chance to look at him again. He smiled ready to face it. Then he felt Senkuu stand up. It was going as he expected.

"Then I'll go back to the village," Senkuu explained without the other asking him. "See you tomorrow, mentalist, don't be so late..."

"I'll hurry, without someone looking at me this bath is not as interesting as usual..."

But what Gen had not foreseen was that Senkuu could be made closer, touching his back to be able to whisper something in his ear.

"Do you want me to stay, Mentalist?" he asked, smiling between the words.

"You could stay if you wanted to take a bath too... are you hot?" he insisted, tilting his head to the right, giving him more space for his next move, but Senkuu did not fall into his neat trap.

"It's hot, but maybe if I stay I could feel even hotter..."

"But it's really pleasant, isn't it? A heat that caresses you from within and pushes you to want more," said Gen, "You don't want more, Senkuu-chan?"

Gen didn't want to play easily.

"Being ambitious is perhaps one of the most important characteristics for anyone who wants to achieve something." Senkuu said after a few seconds. "Of course I want more."

"Then you should try... you deserve it and if for a couple of hours you leave your mind to rest, you may also notice that it was the right thing to do."

Gen would have liked to continue but Senkuu's hands tightened around his hips and the bodies clung to each other. The mentalist bit his tongue so as not to flinch when he felt him press behind his back. He put a finger to his own mouth as the young scientist's breath tickled his half-uncovered neck.

"Goodnight, Mentalist," Senkuu chanted carefully, making his eyes widen.

"But... Senk..." he stammered, feeling his grip fade. For a moment his seduction capacity also failed. His calculations were infallible when it came to knowing human nature and even Senkuu's infallible keen mind would not take away his talent.

"Or do you want to beg me to stay here?"

"No, you can go, Senkuu-chan," he replied gritting his teeth so as not to get upset. If he wanted to waste some time flirting, he would not have missed the opportunity to see Senkuu Ishigami begging him to touch him.

"Perfect, see you tomorrow… Mentalist..."

Senkuu stepped back and turned to go through the woods. Gen would have expected him to stay there, to help him take off his clothes - which Senkuu would have gladly done, if he hadn't considered that the mentalist would probably have given him the torment for giving in to his instincts - but he had found the way to evade his choice. He passed the treesand turned left instead of the small path to the right. He walk on the grass and climbed the trunk that had fallen last winter during a thunderstorm. Panting, he managed to get to the other side, thus shifting his observation point. Now it was slightly to the west of the place where Gen swam but also to know him was there without clothes...

He was regretting saying no. He would have had a good view of Gen in the water, without having to walk more meters.

Suddenly he saw Gen - still wearing his robe - walking along the shore to approach the tree where Senkuu was hiding to look at him as if Gen were looking for something.

Actually, he was looking for someone. 

For him.

Senkuu smiled and shook his head. He got up (he had practically fallen to the ground from fatigue) and went back. Seeing that Gen knew him so well and that he hadn't taken anything off because he wanted his gaze on himself excited him even more.

As he walked back to the village, Senkuu realized that both he and Gen would have many things to say the next day.


End file.
